This a competing continuation application of an ongoing research study to evaluate the role of transrectal ultrasonography (TRUS) for the detection and staging of carcinoma of the prostate. A network organization has been formed with the applicant institution and Baylor University and Case Western Reserve University to complete 3 protocols. PROTOCOL 101: TRUS prior to radical prostatectomy. Patients with biopsy proven carcinoma of the prostate will have 2 independent digital rectal examinations and TRUS performed according to the group guidelines. Detailed information about the echo pattern of the prostate, the regional ultrasound findings, the digital rectal examination, and PSA will be used to determine the characteristic appearance of prostate cancer, findings which suggest extra capsular extension or seminal vesicle invasion, and the relative staging accuracy of TRUS. The pathologic interpretation from whole mount histologic sections of the prostate will be compared to the ultrasound I images. 500 patients will be registered onto this study. PROTOCOL 102: TRUS prior to transurethral prostatectomy. 1000 patients will undergo TRUS and biopsy as indicated before transurethral prostatectomy to determine the ability of the procedure to detect stage A (nonpalpable) tumors. PROTOCOL 103: TRUS prior to cystoprostatectomy. Calculation of sensitivity and specificity in detecting cancer requires careful histologic examination of the entire prostate as can be performed after cystoprostatectomy. 180 patients will be entered onto this prospective study and the accuracy of TRUS in detecting cancer calculated. Receiver operator characteristics (ROC) are incorporated into this and other protocols to increase the clinical relevance and interpretability of results. Inter and intra observer variability in the interpretation of TRUS will be calculated by circulating protocol films to 8 different reviewers and by re-review of a percentage of the films. A statistical and coordinating center has been established to record and analyze the results. Serum will be stored in a central bank and prostate specific antigen performed all on patients at a core laboratory.